344 



FOODS, COMPOSITION AND NUTRITIVE VALUES OF. 



albuminoids, the carbohydrates, and the fats 

 are transformed into fat, and that the fat 

 thus formed is consumed, either before or after 

 being stored as body-fat. 



It appears, then, that protein is the most im- 

 portant constituent of our food, because, while 

 it performs the functions of each of the other 

 two chief nutrients in being transformed into 

 fat and in being consumed for fuel, it has 

 a most weighty office of its own in forming 

 the basis of the blood and in building up the 

 muscular and other nitrogenous tissues, an 

 office which no other nutrient can perform at 

 all. And, as we shall see further, in examin- 

 ing the pecuniary cost, protein is the dearest 

 as well as most important of the ingredients 

 of foods. 



The same experimental research which has 

 revealed to us the ways in which our food sup- 

 plies our bodily wants, has shown us how to 

 estimate the relative nutritive values of differ- 

 ent foods from their chemical composition. 

 The estimates are only approximate, because 

 the nutritive effects are influenced by various 

 conditions, some of which research has not yet 

 definitely explained, while others vary with 

 the nature of the food or of the user, so that 

 the value of a given food in a given case may 

 vary from the standard set by the analysis. 

 These sources of uncertainty are nevertheless 

 so narrowed down by late investigation, and 

 the errors confined within such limits, that by 

 intelligent use of the facts at our disposal we 

 may judge very closely from the chemical com- 



position of a food what is its value as compared 

 with others of the same class, at any rate, for 

 our nourishment. 



Chemical Analysis of Foods. The following 

 tables give the composition of a number of the 

 more important kinds of animal and vegetable 

 foods. The details will perhaps be best ex- 

 plained by an example. A sample of beef, sir- 

 loin, of medium fatness, was found to consist 

 of about one fourth bone and three fourths 

 flesh, edible substance. The flesh was ana- 

 lyzed and found to contain, nearly : water, 60 

 per cent. ; protein, 19 per cent. ; fats, 20 per 

 cent. ; mineral matters, 1 per cent. Calcu- 

 lated upon the whole sample of meat, of which 

 one fourth, or 25 per cent., was bone and other 

 refuse, and 75 per cent, flesh, the analysis would 

 stand as in the schedule below, in which the 

 composition of the flesh by itself and that of 

 the meat, bone, and all, are both given : 



This very imperfect analysis may be stated 

 in the following form, as is done in the tables 

 beyond: * 



CONSTITUENTS OF SAMPLE OF BEEF, SIRLOIN. 



Table I, on page 345, gives the composition 

 of a number of animal foods, mostly from late 

 American analyses. It is only a short time 

 since analyses of American meats, fish, etc., 

 have been undertaken in any considerable num- 

 ber, and those as yet accomplished are far from 

 sufficient for a complete survey of the subject. 

 Indeed, the -work already done can be regard- 

 ed only as a beginning. Still, the figures will 

 give a tolerably fair idea of the composition of 

 the articles named. 



The analyses of this table, with the exception 

 of a few from European sources and indicated 

 by italics, are selected from the results of the 

 investigation referred to above, as conducted 

 under the auspices of the Smithsonian Institu- 

 tion and the United States Fish Commission. 

 The specimens of meats were purchased from a 

 dealer in Middletown, Conn., and said by him 

 to be "fair average samples of the better kinds 



of meats." A side of beef, freshly brought in 

 winter from Chicago, and said to be a good 

 specimen of first-class " Chicago beef," was cut 

 into about twenty-five pieces in the ordinary 

 way. From each a sample fairly represent* 

 ing the whole cut was taken and analyzed. 

 Thus the composition of each piece and of the 

 whole side was learned. The composition of 

 one of the leanest portions, the round, a mod- 

 erately fat piece, sirloin, a very fat portion, 

 flank, and of the whole side, together with a 

 tongue, liver, and heart from another animal, 

 are given in the table. The samples of a side 

 of mutton and of parts of the same side were 

 obtained and analyzed in like manner, as were 

 those of the other meats and fowl. The speci- 



* The tables contain also columns for carbohydrates, etc., 

 which occur in milk and in some shell-fish, but are not found 

 in ordinary meats in sufficient amount to warrant their inser- 

 tion in such tables as these. 



